Enter a recent race result to get your VDOT score and all five training zone paces — easy, marathon, threshold, interval, and repetition — based on Jack Daniels' proven methodology.
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VDOT is a single number that summarises your current running fitness. Developed by exercise physiologist Jack Daniels in his landmark book Daniels' Running Formula, VDOT is derived from your recent race performance and acts as a practical stand-in for VO2max — the maximum rate at which your body can consume oxygen during exercise.
Two runners with the same VO2max can perform very differently depending on their running economy (how efficiently they use oxygen at a given speed). VDOT neatly captures both factors because it is based on actual race results rather than laboratory measurements.
30–40
Beginner runner
5K in 30–38 min
45–55
Intermediate runner
5K in 22–27 min
60–75+
Advanced / competitive
5K in 16–20 min
Daniels identifies five distinct training intensities, each with a specific physiological purpose. Using the wrong pace for a given workout is one of the most common training mistakes — going too hard on easy days or not hard enough on quality days.
Easy pace should feel genuinely easy — you can hold a full conversation without effort. It accounts for 60–70% of your weekly mileage and drives the majority of your aerobic adaptations: increased capillary density, stronger heart muscle, and improved fat-burning efficiency. Runners chronically run their easy days too fast, accumulating fatigue without proportional fitness gains.
Marathon pace sits between Easy and Threshold — faster than a jog but not a sustained hard effort. It is used in long runs and marathon-specific workouts (e.g., 18 miles with the final 10 at M pace). This zone is most relevant for marathon and half marathon runners building race-specific endurance.
Threshold pace is “comfortably hard” — you can speak in short sentences but not carry on a conversation. Running at this intensity teaches your body to clear lactate faster, raising your lactate threshold and allowing you to run faster before fatiguing. Classic T workouts are 20-minute steady tempo runs or cruise intervals (e.g., 4×1 mile with 1-minute rest).
Interval pace is hard — approximately 3–5 minutes of sustained effort per repeat. It targets VO2max directly, increasing your aerobic ceiling. Classic I workouts are 5×1K or 6×800m with equal rest. Because of the high stress, I-pace volume should be limited: Daniels recommends no more than 8% of weekly mileage at this intensity.
Repetition pace is fast but controlled — shorter than Interval reps (200–400m) with full recovery between each. R pace improves running economy, turnover, and neuromuscular efficiency. It is not all-out sprinting; the goal is excellent form at a high speed. Full recovery (walking or jogging back) is essential to maintain quality across all reps.
This calculator uses two well-established formulas to convert your race performance into VDOT and training paces.
T5K = RaceTime × (5000 / DistanceMeters)1.06
This converts any race distance to an equivalent 5K time, using Pete Riegel's widely-used fatigue exponent.
VDOT ≈ 29.54 + 5.000663 × v − 0.007546 × v²
Where v = 5 km / (5K time in minutes). The resulting VDOT is then mapped to training paces via Daniels' published lookup tables, with linear interpolation between table entries.
VDOT is a number that represents your current running fitness level, derived from a recent race performance. It was developed by exercise physiologist Jack Daniels and is essentially a proxy for VO2max adjusted for running economy. A higher VDOT means better running fitness. A recreational runner might have a VDOT of 35–45, while elite marathoners often exceed VDOT 75.
The paces are highly accurate when you use a recent, maximal race effort as your input. The VDOT formula is validated across thousands of runners and used by coaches worldwide. The key caveat is that the race must be recent (within the last 8–12 weeks) and represent a genuine all-out effort.
According to Daniels' methodology, approximately 60–70% of your total weekly mileage should be at Easy or Recovery pace. The remaining 30–40% is distributed among quality workouts at Threshold, Interval, and Repetition paces.
Update your training paces every time you run a new race that represents your current fitness — usually every 8–16 weeks during a structured training cycle. Avoid updating paces based on workout times alone; use official race results for the most reliable VDOT.
5K and 10K races tend to give the most consistent results for most runners. Very short races (1 mile) can be skewed by anaerobic capacity, while marathons can vary based on fueling strategy and pacing.
Threshold (T) pace is “comfortably hard” — you can speak in short sentences. It targets your lactate threshold in 20-minute efforts. Interval (I) pace is harder — genuinely difficult, sustained for 3–5 minutes per rep. Interval training directly elevates VO2max through repeated hard efforts with recovery.